Night falls on a Syrian rebel-controlled area Thursday as destroyed buildings, including Dar Al-Shifa hospital, are seen on Sa'ar street after airstrikes targeted the area last week, killing dozens in Aleppo, Syria. (ASSOCIATED PRESS / Narciso Contreras)

MASNAA, Lebanon (AP) — Syrian security forces killed as many as 20 Lebanese gunmen who were fighting alongside rebels in Syria on Friday, raising tensions amid mounting fears that the Syrian civil war is enflaming the region.

The Lebanese security officials said the gunmen were killed as they tried to enter the Syrian town of Tal Kalakh, near the Lebanese border. The officials asked that their names not be used because they were not authorized to speak publicly.

Syrian state-run media also reported that Lebanese gunmen were killed. But the SANA report said there 17 — not 20 — fighters. The discrepancy could not immediately be reconciled.

The Lebanese gunmen were Sunni Muslims, as are the vast majority of Syria’s rebels. Syrian President Bashar Assad — along with his most elite troops — belong to the Alawite sect, an offshoot of Shiite Islam.

Lebanon is particularly vulnerable to getting sucked into the conflict in Syria. The countries share a complex web of political and sectarian ties and rivalries that are easily enflamed. Lebanon, a country plagued by decades of strife, has been on edge since the uprising in Syria against Assad began in March 2011, with deadly clashes between pro- and anti-Assad Lebanese groups erupting on several occasions.

The deaths came as rebels have tried to close in on the Syrian capital, Damascus, in recent days.

On Friday, Syrian soldiers fought rebels in and around the capital as Internet and most telephone lines were blacked out for a second day. But the intense battles around the country’s international airport appeared to have calmed.

The airport road had reopened by Friday and the head of the Syrian Civil Aviation Agency, Ghaidaa Abdul-Latif, said the airport was operating “as usual.” A day earlier, heavy fighting forced the closure of the road and airlines canceled international flights to Damascus.

The Britain-based Syrian Observatory for Human Rights and residents who were interviewed while leaving Syria on Friday said there was still sporadic fighting in pockets of the capital and on the outskirts.

A minibus driver said he heard explosions in the distance as he drove through Damascus.

“There are extreme security measures in Damascus today,” said the driver, who asked to be identified only by his first name, Mohamad, out of fear for his personal safety.

“We were stopped at several checkpoints,” he told The Associated Press. “Our IDs were checked and they even opened all the bags and suitcases.”

He spoke as he crossed into Lebanon, driving a minibus packed with woman and children.

The communications blackout has raised fears of an explosion of fighting outside the public gaze. The Internet has been a key tool of activists over the course of the Syrian conflict, which started 20 months ago and has left more than 40,000 people dead, according to activists.

Syrian authorities previously have cut Internet and telephones in areas ahead of military operations. On Friday, some land lines were working sporadically.

In the southern part of the capital, the main road to Damascus’ airport reopened early Friday afternoon, according to the Observatory. Intense clashes broke out after midnight in villages and towns near the facility but the area was calm by the late morning, the group said. It said rebels were able to destroy several army vehicles near the airport.

The Observatory, which has a network of activists around Syria, reported fighting in other southern neighborhoods of Damascus, including Tadamon and Hajar Aswad. The group said it was able to contact its sources who used satellite telephones.

According to the Observatory and witnesses who crossed into Lebanon, several suburbs — including Aqraba, Beit Saham and Daraya — also saw heavy fighting.

By contrast, a man who crossed into Lebanon with his wife and son said it was quiet Friday nearby in Damascus’ western suburb of Zabadani — a far cry from a day earlier, when the neighborhood was “like hell.”

“The battles were flaming throughout the day,” he said, asking not to be identified because he was afraid of repercussions.

But much of Thursday’s violence was focused on southern suburbs near the airport. The surrounding districts have been strongholds of rebel support since the uprising began.

Two Austrian soldiers assigned to the United Nations Disengagement Observer Force in the Golan Heights were wounded Thursday when their convoy came under fire on the way to the airport, Austria Press Agency said.

The two were transferred to Israel for treatment Friday and their condition is not life-threatening, said David Ratner, a spokesman for Rambam Hospital in Haifa. He said the two soldiers suffered gunshot wounds — one to the chest and the other to the hand.

With pressure building against President Bashar Assad’s regime on several fronts and government forces on their heels in the battle for the northern commercial hub of Aleppo, rebels have recently begun pushing back into Damascus after largely being driven out of the capital following a July offensive. One Damascus resident reported seeing rebel forces near a suburb of the city previously deemed to be safe from fighting.

Regime forces have suffered a string of tactical defeats in recent weeks, losing air bases and other strategic facilities. The government may be trying to blunt additional rebel offensives by hampering communications.

Analysts say the regime appears to be the culprit for the Internet outage. Syria has several cables that connect it to the outside world, and all of them would have had to be cut at once for a complete outage.

As the rebels and government vie for the upper hand in an increasingly bloody struggle, the conflict’s toll on civilians is worsening.

The U.N. refugee agency said Friday it found desperate conditions in the Syrian city of Homs, where thousands of people are living in unheated shelters and a quarter of a million people are displaced from their homes.

An assessment team visiting this week saw half of the city’s hospitals shut down and “severe shortages of basic supplies ranging from medicine to blankets, winter clothes and children’s shoes,” agency spokeswoman Melissa Fleming said.

As the violence rages, Syria’s neighbors are increasingly being drawn into the country’s civil war in a variety of ways, whether militarily or as a result of an exodus of Syrians fleeing the fighting.

Syria is believed to have several hundred ballistic surface-to-surface missiles capable of carrying chemical warheads — a particular concern for Turkey, a NATO member.

On Friday, NATO said it will deploy Patriot missiles to Turkey’s border with Syria “within several weeks” after the move is approved.

Spokeswoman Oana Lungescu said a team assessing possible sites for the air defense systems is making good progress and is expected to report back soon. This opens the possibility that foreign ministers of the 28 member countries, meeting in Brussels on Tuesday and Wednesday, could make the final decision.

Germany, the Netherlands and the U.S. have the advanced PAC-3 model Patriots that Turkey needs to intercept ballistic missiles. Parliaments in Germany and the Netherlands must also approve the deployment.